Effect of lipoarabinomannan from Mycobacterium avium subsp avium in Freund’s incomplete adjuvant on the immune response of cattle

The aim of the present study was to determine whether lipoarabinomannan (LAM), in combination with Freund’s incomplete adjuvant (FIA), was able to improve cell-mediated and antibody-mediated immune responses against ovalbumin (OVA) in cattle. Twenty-three calves were assigned to four treatment groups, which were subcutaneously immunized with either OVA plus FIA, OVA plus FIA and LAM from Mycobacterium avium subsp avium, FIA plus LAM, or FIA alone. Lymphoproliferation, IFN-γ production and cell subpopulations on peripheral blood mononuclear cells before and 15 days after treatment were evaluated. Delayed hypersensitivity was evaluated on day 57. Specific humoral immune response was measured by ELISA. Inoculation with LAM induced higher levels of lymphoproliferation and IFN-γ production in response to ConA and OVA (P < 0.05). Specific antibody titers were similar in both OVA-immunized groups. Interestingly, our results showed that the use of LAM in vaccine preparations improved specific cell immune response evaluated by lymphoproliferation and IFN-γ production by at least 50 and 25 percent, respectively, in cattle without interfering with tuberculosis and paratuberculosis diagnosis.

Control of Mycobacterium fortuitum and Mycobacterium intracellulare infections with respect to distinct granuloma formations in livers of BALB/c mice

Mycobacterium fortuitum is a rapidly growing nontuberculous Mycobacterium that can cause a range of diseases in humans. Complications from M. fortuitum infection have been associated with numerous surgical procedures. A protective immune response against pathogenic mycobacterial infections is dependent on the granuloma formation. Within the granuloma, the macrophage effector response can inhibit bacterial replication and mediate the intracellular killing of bacteria. The granulomatous responses of BALB/c mice to rapidly and slowly growing mycobacteria were assessed in vivo and the bacterial loads in spleens and livers from M. fortuitum and Mycobacterium intracellulare-infected mice, as well as the number and size of granulomas in liver sections, were quantified. Bacterial loads were found to be approximately two times lower in M. fortuitum-infected mice than in M. intracellulare-infected mice and M. fortuitum-infected mice presented fewer granulomas compared to M. intracellulare-infected mice. These granulomas were characterized by the presence of Mac-1+ and CD4+ cells. Additionally, IFN-γmRNA expression was higher in the livers of M. fortuitum-infected mice than in those of M. intracellulare-infected mice. These data clearly show that mice are more capable of controlling an infection with M. fortuitum than M. intracellulare. This capacity is likely related to distinct granuloma formations in mice infected with M. fortuitum but not with M. intracellulare.

Cytokines involved in resistance to mycobacterium avium in a mouse model of infection

To determine the role played by different cytokines in the induction or expression of protective immunity to Mycobacterium avium we administered neutralizing monoclonal antibodies specific for those cytokines to mice infected with a clinical isolate of M. avium. Our results showed that interleukin [IL]-6 and IL-12 are involved in the induction of T cell-dependent immunity and that such immunity was mediated by interferon-gamma [IFN-gamma] and tumour necrosis factor-alpha [TNF-alpha]. Also, induction of innate immunity required IL-12 and was expressed through the secretion of IFN-gamma and TNF-alpha

Protective response in guinea pigs exposed to Mycobacterium aviumintracellulare/M. scrofulaceum, BCG & south Indian isolates of M. tuberculosis.

The protective immunity resulting from exposure to nontuberculous mycobacteria (NTM), BCG and virulent mycobacteria in different sequences was studied in the guinea pig model employing strains prevalent in the south Indian BCG trial area and time kinetics to observe the immuno-modulation. The findings suggest that during the early course of challenge infection in guinea pigs there was no interference with the immunity due to BCG, by prior exposure to NTM. In the animals sensitised with M. avium intracellulare before immunisation, the challenge infection was localised and confined to the site of inoculation, and only a few organisms reached the spleen. However, at the later stages of the infection, as seen by the spleen viable counts at 12 wk, it appeared that the barrier at the localised site of infection may not be intact in the animals with prior exposure to NTM, and a few organisms disseminate to the spleen.

La intradermo-reacción con sensitinas en población paraguaya no becegeizada / Intradermal reaction with sensitins in paraguayan population who had never received BCG vaccine

Este trabajo constituye la 2a. parte del trabajo previo denominado "La intradermo-reacción con sensitinas en población paraguaya". En la presente investigación hemos incluído exclusivamente a individuos que no habían recibido la vacuna BCG, encontrando, sobre 44 pacientes estudiados, una tasa de reactores significativos de 29,7 por ciento a las sensitinas utilizadas. Dentro de estos pacientes reactores, constatamos en ambos estudios un neto predominio de reactores al M. avium (60 por ciento y 90,9 por ciento respectivamente). Con esto, queda comprobada la alta tasa de infección de la población paraguaya a las micobacterias no TBC y específicamente al M. avium

Response to tuberculin PPDs prepared from Mycobacterium tuberculosis and other Mycobacteria in children of Buenos Aires

Se estudiaron 849 niños: 220 de ellos menores de 6 años y los restantes 629, de 6 a 16 años. El 50,8% presentaba una cicatriz debido a la vacunación con BCG. La población estudiada se dividió en 7 grupos, a los que se les aplicó tuberculina PPD M. tuberculosis (RT 23) en un antebrazo, en dosis de 2 o de 5 UT, y PPD (sensitinas de M. avium, M. intracellulare o M. kansasii), en dosis bioequivalentes a 2, 5 o 10 UT, según el grupo. Las respuestas observadas a las 72h se clasificaron, de acuerdo a los diámetros de reacción en (A) "puras" a PPD RT 23, cuando el sujeto era negativo a la sensitina, (B) "cruzadas", cuando la respuesta a ambas PPD era semejante y (C) "significativas" a la sensitina: cuando el sujeto sólo reaccionaba a ella y no al PPD RT 23 o cuando la respuesta a la sensitina era mayor en 4mm o más, que al PPD RT 23. Un 10,5% de los 172 niños a los que se aplicó PPD de M. avium, en dosis de 2 o 5 UT, dieron reacciones "significativas" a esta sensitina. La misma reacción se observó en un 2,0% de los 399 niños del grupo al que se aplicó PPD de M. intracellulare en dosis de 2,5 o 10 UT. Finalmente, el porcentaje de reactores "significativos" a la sensitina de M. kansasii, que fue empleada en dosis de 5 o 10 UT, fue 0,7% (2 de los 278 niños de ese grupo). Se observó en general una correlación positiva entre la edad y el porcentaje de respuestas significativas a las sensitínas de M. avium, M. intracellulare y M. kansasii y también, aunque no siempre, entre la vacunación previa con BCG y las respuestas correspondientes. En este estudio la importancia de las micobacterias diferentes del M. tuberculosis como causa de sensibilización fue relativamente baja, predominando el M. avium sobre las otras 2 especies analizadas

Anti-leprosy vaccines--field trials and future prospects.

Development of a vaccine for prevention of leprosy is today one of the major challenges for bio-medical sciences. Two vaccines containing (i) M. leprae + BCG and (ii) ICRC, a cultivable mycobacterium, have reached advanced stage with reference to human trials. This article describes comparative features of two vaccines and mechanism of their action. Future possibilities with reference to anti-leprosy vaccine are also discussed.

Antigeneic cross-reactivity between ICRC-bacilli and M. leprae--"in vitro" evaluation.

Leucocyte migration inhibition, in presence of specific particulate antigen, is a good correlate of CMI. It can detect small differences in related antigens. In the present study, LMI was used to study the cross-reactivity between ICRC bacilli and M. leprae and also to examine the antigenic relationship amongst different ICRC isolates. The study showed a close antigenic cross-reactivity in lepromin and ICRC-in. LMI has brought out strain differences in two ICRC culture isolates, C-44 and C-75. The data appear to elucidate the possible strain specific antigenic relationship of M. leprae with its culture isolate e.g. ICRC strains. This may have important bearing on the development effective antileprosy vaccine for human use.